Method of carroting fur and composition for use therein



, whether; the carroting solution .betha Patented Dec. 29, 1942 METHODOF oAnno'nNo run AND COM- rosrrron roe USE. THEREIN Brookfiem Center,Conn.,

Constantine F. Fabian,

v assigrior to The Nonpany, Danbury, Coma,

necticut Mercuric Carrot Coma corporation of 'Con- No Drawing.Applicatiofl December 27, 1941, Serial No. 424,596

(or. a-uz) Claims.

The present invention relates to a method of carroting fur andparticularly to a method which eliminates the manuallabor of brushingthe carroting solution upon the fur as is presently done. The carrotingof fur is well known in the art of felt making and comprises thetreating of the fur with a chemical solution which renders the furcapable of felting. The chemical solutions used in the treatment aboveoutlined are gen-0 erally known as carroting solutions. Many of thesecarroting solutions are known, the vast majority of which are composedof mercury nitrate and nitric acid in varying proportions inaqueous so;lution. Recently, however, the non-mercuric carroting solutionsdescribed in Fabian latent No. 2,169,997, issued August 22, 1939, aswell as in the following patents issued to Fabian and 'Sachanen, No.2,048,645, issued July 21, 1936, Nos. 2,087,954,2081855, 2,087,856,2,087,857 issued July 20', 1937,. and No. 2,144A87 issued Jan.

17, 1939, have come into wide use. The method of the present inventionis, however, applicable above-mentioned patents or the older mercurynitrate-nitric acid solution. or other known carroting solutions.

The presentcommon cation of the oarroting solution to the-furs is, asindicated above, the brushing of the for with the solution while the furis on the pelt, with subsequent drying usually performed at an elevatedtemperature. It has been found impossible to carrot the fur by immersioneither while on the pelt or after cutting the fur therefrom, Appan entlyfur which has been immersed in the carroting solution undergoes achemical change throughout its length and this apparently, possibly dueto the fact that strains set up in the fibres when treated for only aportion of their length are absent when treated throughout their length,prevents the subsequent felting action desired.

Such a manual method has numerous disadvantages. The brushing operationis not unis formly performed due both to variation between dilierentoperators and to fatigue. It is obvious that this lackof uniformity oftreatment isimportant when it is considered that many fur cutting plantsproduce 3000 lbs. ormore of carroted fur daily, which means thatapproximately 75,000

y usedmethod forappli- I example back to back, which is done manuallyand is, of course, subject to the 'same lack of uniformity.

Even more important than the above is the fact that when the brushingoperation is performed there is danger to the operators since it ispractically impossible to keep from splashing the carroting solution onthe hands and face, and furthermore the fumes given off by the solutionare frequently inhaled.

In the past many explanations have been givon as to exactly whatoccurred during the carroting operation. Among the explanations was onewhich was based on the assumption that the furffibres were coated withsome .kind of waxy material which was removed during the carroting andwhich made it possible to felt the fur. In accordance with this theory,attempts were made to carrot the fur by the useoi mechanical forces, asfor example by theemployment of abrasives or metal brushes. In TweedyPatent No. 339,349, issued April 6, 1886, it was suggested that. furcould be;carrotedby placingit ina tumbling barrel together withabrasives in powdered form, which would remove the waxy coating andleave the Such a theory is at present believed to be ertion into the furto skins have to beiridividually handled in the brushing operation: v IFurthermore, the drying operation as at present performed requires thestacking of the pelts,

in some instances in special arrangements, for

. material capable of carrying roneous. In any event methods such asthat set forth in the above-mentioned Tweedy patent have never beencommercially successful.

:My present invention 'comprises a method whereby the carrotingsolution'is applied to the fur while onthe pelt by means of materialcapable of absorbing the carroting solution, mixed with the firstmentioned material into the fur to the desired extent, the mixture beinghereinafter called a carroting mixture. a

It is an object of my invention to improve the method of furcarrotingand to provide a composition of matter for carrying the carrotingsoluthe proper extent to bring about the desired carrotingeffect.

It is another object of my invention to provide sucha process or methodwhereby the time required for'drying the fur after carroting is re ducedto a minimum.

It is still another object of my invention to provide a process whichwill eliminate the brushing or spraying of the carroting solution on theskins, thereby increasing the uniformity of the carroting aotionandreducing the hazards and expenses involved in carroting operations.

A further object of my invention is to provide a carroting process inwhich the individual treat fur in a feltable condition. y

ment of the skins is eliminated, and replaced by treatment in volume, ormass production, thereby increasing the production rate immensely. In mynew process the carroting solution, which may be any 'of the knownworkable solutions, is

In general, as is indicated above, the material should be in a finelydivided or powdered state.

These absorbent materials are wetted with the I carroting solution andare then brought into contact for a predetermined period of time,variablein accordance with the type of fur being treated,

with the fur while still on the Pelt.

Since the absorbent materials, hereinafter called conveyors since theyconvey the carroting solution to the fur, are non-reactive. they'do notconsume the carroting solution nor any of the ingredients thereof, butrather give 01! the solution to the fur with which the reaction proceedsand on which the ingredients of the carroting solution are consumed. Itwill be obvious that the period of time during which the conveyors arein contact with the fur must be sufllciently great to give the propercarroting eifect and that there is no advantage to be gained by leavingthe materials in contact subsequent to the establishment of equilibriumbetween the moisture content of the conveyors and that of the fur.

Due to the fact that the conveyors are of alow specific gravity, they donot possess the property of penetrating into the fur on the pelts. Ihave found that if the conveyors, either prior'or subsequent to beingwet with the carroting solution, are mixed with neutral non-reactive,nonabsorbing, ground materials of relatively high specific gravity, atleastgreater than that of water, then the conveyors are carried into thedepth of the fur on the skin by these last mentioned materials, whichfor this reason will hereinai'ter be called penetrators. Examples ofsuch 45 penetrators are sand, ground or powdered abrasives, and groundstone not containing'carbonates. Experiments indicate that penetratingcapacity varies somewhat with the size of the penetrator particles, thebest results being obtained with a size of from 20 to 30 mesh.

Since, as has been stated hereinabove, the carroting effect occurs onlywhen the fur fibre has been treated with the'carroting solution over aportion of its length, it is obvious that the proportion of conveyorsand penetrators comprising the carr ting mixture will depend upon thetype "and quality of the pelts. Generally speaking, the- I nger andthicker the fur on the skin, the larger :the amount of nenetrator whichshould beincluded in the mixture.

In most cases the optimum result is secured when the conveyors andpenetrators are mixed in the proportion of one to one by weight. TheconvIgjeyors and penetrators must be thoroughly mixed and furthermorethe carroting solution must be thoroughly mixed with either the conveyoralone before its mixture with the penetrators, or with e mixture ofpenetrators and conveyors.

indicated above, any of the known operlb'l'e carroting solutions may beutilized. I have (1, however, that the concentration of the harrotingsolution should b considerably higher when using my method than whenusing the old nigthod oi brushing. In most cases the concentration hasto be increased in the neighborhood of from 30% to 50%. Thus if thestrength of the carroting solution measured by the Baum hydrometer is 9degrees, when the old brushing method is utilized. the st of the samecarroting solution when used in my method should be between-11.8 degreesand 13.5 degrees.

I have further found that when my new method is utilized the addition ofglue, gelatin, or furfural to the carroting solution, prior to itsincorporation in the carroting mixture, considerably improves thecarroting effect and produces fur with greater felting speed. It is mybelief that glue, gelatin, or furfural, when added to the carrotingsolution, facilitates adhesion between the conveyors and penetratorsthereby improving the uniformity of penetration by the conveyors intothe depth. of the fur.

In any event, whether this belief be'correct or not, experiment hasshown that the addition of the abovementioned substances does improvethe action and produce a superior carroting effect. The amount ofadhesives in the carroting solution may vary considerably but practicehas shown that the use of from 3 to 5% by weight, based on the totalweight of the ready-to-use carroting solution, produces the desiredresult.

The conveyors and penetrators must be thoroughly mixed and wetted withthe carroting solution before utilizing them in the carroting process.While the amount of the conveyors may vary rather widely, practice showsthat between 10% and 25% of the weight of the pelts to be carroted isproper; for example if 100 pounds of rabbit skins are to be carroted bymy process, then between 10 and 25 pounds of conveyors are required. 7

The amount of the carroting solution used with the conveyors dependsupon the yield of the fur from the particular pelts. Experience hasshown that each gallon of the carroting solution is capable of carrotingabout eight pounds of fur, this again, of course, depending to someextent on the type of fur. However, in general the amount stated aboveis correct. For example, 11' 100 pounds of skins areto be carroted andthe yield of fur from this type of skin is known to be about 32 pounds,then approximately four galions of the carroting solution is required towet the mixture of conveyors and penetrators which would in this caseconsist of approximately fifteen pounds of conveyors and fifteen poundsof penetrators.

While many methods might be employed for treating the skins with thecarroting mixture, I have found that tumbling is a preferable method. Inthis method a drum which is of substantially the same construction asthe drum used for softening pelts in the fur cutting industry, hasplaced in it the skins to be treated. preferably in alternate layerswith the carroting mixture, and the drum is thereafter rotated for a'with the drum speed, the time to perform the carroting operation mayvary within wide limits but in general this period of time will bebetween three and six hours.

v the second or perforated drum. ,they are rotated for a period of timedetermined by observation.

7 carroting solution.

As in Example I the skins are thereafter placed Subsequent to thecarroting operation, with While the above has described my new proc---ess, examples of the complete process are set forth below:

' Example I 100 pounds of English unpulled skins are to be carroted. Thefur yield of such skins-is known to be approximately 32%. 15 pounds ofthe conveyor, in this instance sawdust, and15 pounds of the penetrator,a ground abrasive, are thoroughly mixed and wetted with four gallons ofthe carroting solution containing 4% of adhesive, in this instancegelatin. A layer of skins is placed in the drum and a portion of theprepared carroting mixture is spread on this layer of-skins. The secondlayer of skins is then placed in the drum and spread with the carrotingmixture, and this process is continued until all of the skins are in thedrum and all of the prepared mixture has been used. In each instancewooden bars are placed between the layers of skins in order to separatethem and facilitate the action of the carroting mixture upon the fur.After the drum has been charged, the opening is closed, and then thecarroting operation is started by rotating the drum at a speed ofapproximately 40 revolutions per minute, this operation being continuedfor four hours. rotation preheated and preconditioned air is introducedinto the rotating. drum through the normal axial opening, care beingtaken not to have the temperature of the air above 120 F. Thisintroduction of preheated air into the drum facilitates the carrotingefiect and provides for greater uniformity thereof, and likewise causesAfter the operation described above the skins are removed from the firstdrum and placed in In this drum This period is sufficient to remove thedry transmitters and conveyors from the fur. After this operation thefur is completely carroted and dried and is also free from Example II100 pounds of American double ring skins are to be carroted. This typeof skin is well known in the industry and is known to be one of the mostdifiicult to carrot. The yield from this type of fur is relatively high,being about forty pounds of fur from each one hundred pounds of pelts.In this instance twenty pounds of conveyors-are mixed with twenty poundsof penetrators, and the resulting mixture wetted with five gallons ofThe skins and carroting mixture are placed in the first drum in alter-'nate layers in the same'manner as described in connection with ExampleI, and the drum is thereafter rotated at a speed of approximately 60revolutions per minute for. approximatelysix hours. During the firstthree hours of the six the carroting operation is performed and dur-After the first two hours of in a second drum and rotated for asufiicient time to separate the now dry carroting mixture from the furafter which the skins are ready for further operations in the ordinarymanner.

While I have described preferred embodiments of my invention, it is tobe understood that variationsthereof may be utilized without departingfrom the scope of my invention. Therefore, I wish to be limited not bythe foregoing description but solely by the appended claims.

What is claimed is: i

1. The method of carroting 'fur which com-.

' prises bringing said fur while on the skin into ing the remainingthree hours drying is effected.

intimate moving contact with 'a carroting mixture, said mixturecomprising a relatively heavy powdered penetrating material, arelatively light finely divided absorbing material, and a carrotingsolution absorbed by said absorbing ,material, both said absorbing andsaid penetrating materials being non-reactive to said carrotingsolution.

2. The method of carroting fur which comprises bringing said fur whileon the skin into intimate moving contact with a carroting mixture, saidmixture comprising a relatively heavy powdered penetrating material,arelatively light finely divided absorbing material, and a carrotingsolution, including an adhesive absorbed by said absorbing material,both said absorbing and said penetrating materials being non-reactive tosaid carroting solution.

3. The method of carroting fur which comprises bringing said fur whileon the skin into intimate moving contact-with a carroting mixture, saidmixture comprising a relatively heavy powdered penetrating material, arelatively light finely divided absorbing material, and a carrotingsolution including an adhesive of the group glue, gelatin and furfuralin an amount in the range of from 3% to 5% by weight of the carrotingsolution absorbed -by said absorbing material, both said absorbing andsaid penetrating materials being non-reactive to said carrotingsolution. r

4. The method of carroting fur which. comcontainer, bringing said furinto moving contact with a carroting mixture, said carroting mixturecomprising a relatively heavy powdered penetrating material and arelatively light finely divided absorbing material, continuing saidcontact for a period of from two to three hours, and thereaftercontinuing the movement of said skins in said container while causingheated air tocome into contact therewith for a period of from two tothree hours to effect drying of they skins and the carroting mixture.

5. The method of carroting fur which comprises placing said fur while onthe skins in a container, bringing said fur into intimate moving contactwith a carroting mixture, said carroting mixture comprising a relativelyheavy powdered penetrating material and a relatively light finelydivided absorbing material, continuing said contact for a period of fromtwo to three hours, and thereafter continuing the movement of said skinsin said container while causing air heated to a temperature-of'not overF. to come into contact therewith to effect drying of the skins andcapable of absorbing said carroting solution and non-reactive therewith,said penetrator being relatively heavy finely divided material capableof taking said conveyor into the depth of fur on the skin, said conveyorand said penetrator being present in such proportions that the carrotingsolution absorbed by said conveyor will be brought into intimate contactwith the fur throughout a portion of the length of the fur fibre only.

7. A carroting mixture comprising a conveyor, a penetrator and acarroting solution, said conveyor being a material of the class sawdust,natural or synthetic ground sponge, powdered asbestos, capable ofabsorbing said carroting solution and non-reactive therewith, saidpenetrator being relatively heavy finely divided material capable oftaking said conveyor into the depth of the fur on the skin, saidconveyor and said pe'netrator being present in such proportions that thecarroting solution absorbed by said conveyor will be brought intointimate contact with the fur throughout a portion of the length of thefur fibre only.

8. A carroting mixture comprising a conveyor, a penetrator, and acarroting solution, said conveyor being relatively light finely dividedmaterial capable of absorbing said carroting solution and non-reactivetherewith, said penetrator being of the Class sand, ground or powderedabrasives, and ground stone containing no carbonates, capable of takingsaid conveyor into the depth of the fur on the skin, said conveyor andsaid penetrator being present in such proportions that the carrotingsolution absorbed by said conveyor will be brought into intimate contactwith the fur throughout a portion of th length of the fur fibre only.

9. A carroting mixture comprising a conveyor, a penetrator, and acarroting solution, said conveyor being relatively light finely dividedmaterial capable of absorbing said carroting solution and non-reactivetherewith, said penetrator being relatively heavy finely dividedmaterial capable of taking said conveyor into th depth of fur on theskin, said conveyors and penetrators being approximately in theproportion of one to one by weight, said conveyor and said penetratorbeing present in such proportions that the carroting solution absorbedby said conveyor will be brought into intimate contact with th furthroughout a portion of the length of the fur fibre only.

CONS'I'ANTINE F. FABIAN.

